There are a number of problems in manufacturing laser print heads which are fabricated from semiconductor lasers. One problem occurs because there is a limit on how close semiconductor lasers may be to each other on a substrate while still being independently addressable. Specifically, the distance between semiconductor lasers fabricated on the same substrate should be greater than approximately 100 microns for them to be independently addressable. If the semiconductor lasers are disposed any closer to each other than that, interference between adjacent lasers occurs when one of them is excited. For that reason, most attempts in the art at fabricating laser print heads have used isolated semiconductor lasers.
Another problem occurs when attempting to couple light from semiconductor lasers to small closely spaced pixel areas. Specifically, optical fiber elements which have previously been used in the art are incapable of achieving the close proximity of the independent output pixels required for a laser print head.
As a result, there is a need in the art for a laser print head structure which: (1) has semiconductor lasers disposed in close proximity to one another while still being individually addressable; (2) has light transmission means which transmits light from the individual, isolated semiconductor lasers to provide output pixels having spacings between adjacent pixels which are substantially smaller than the spacings between adjacent semiconductor lasers; and (3) has light transmission means with low loss due to absorption or scattering and low crosstalk among its several channels.